The present invention relates to a motor-driven type power assisted steering control apparatus for an automobile in which an auxiliary torque is applied to a steering mechanism by a rotating force from a motor.
A motor-driven type power assisted steering control apparatus of this kind is so constructed that an auxiliary torque is exerted to the steering shaft or the rack of an automobile by means of a transmission device such as a gear or a belt through a gear box by utilizing a driving force given by a motor.
In such control apparatus in which the auxiliary load is removed when a car speed reaches a predetermined level or higher during cruising of the automobile, however, there is a drawback that a steering wheel assumes an unloaded condition when a speed sensor is broken down by a fault such as breaking of a wire.